Log10(LR)
Definition
The base-10 logarithm of the likelihood ratio, sometimes called the weight of evidence (following I.J. Good). A log10(LR) of 1 corresponds to LR = 10, log10(LR) of 2 to LR = 100, and log10(LR) of 3 to LR = 1000. Logarithmic representation is used in verbal scales because LR values span many orders of magnitude.
- Definition
- Base-10 logarithm of the likelihood ratio
- Alternate name
- Weight of evidence (I.J. Good)
- log10(LR)=1
- Equals LR of 10
- log10(LR)=3
- Equals LR of 1000
Common questions
Why do verbal LR scales use log10 rather than the raw LR value?+
LR values can range across many orders of magnitude, and taking log10 compresses that range into evenly spaced categories that map cleanly onto verbal strength-of-support descriptors used in reports.
Who is credited with the weight of evidence concept behind log10(LR)?+
Statistician I.J. Good, whose formulation underlies its use as an additive measure of the evidential weight contributed by independent pieces of evidence.
Related terms
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- Likelihood Ratio (LR)
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- Transposition Fallacy
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- Verbal Equivalence Scale
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